The article starts easy with an overview
of poossible approaches, but then goes quickly into
details of the autoconfiguration system, kernel startup,
bus operations, interrupts and drivers
for the system clock and the serial chip.
He concludes with his
Observations and Comparison with Linux Porting Efforts:
``I've done a few Linux ports before, and the adaptation of NetBSD went at least as smoothly as any of the Linux efforts. In fact, I found NetBSD to have several advantages that made it substantially easier to port to a new platform than Linux, especially for a "newbie" like myself with no previous NetBSD porting experience.''

What else to say? (Nothing, right! :)

While at the topic of porting NetBSD and adding device drivers:
One thing that needs doing in that process is choosing major/minor
device numbers and sort them into tables for block/character
devices. The article mentions an interesting webpage that's
relevant here:
The Auto-Generation Block/Character Device Switch Tables by config(8)
by MAEKAWA Masahide. Yai!